Abstract

Dielectric transparent microspheres are three-dimensional spherical microcavities which provide high Q-factors and a small mode volume leading to strong optical feedback within the cavity [1]. In this present work, we studied the optical properties of symmetrically arranged micrcavities (photonic molecules) with regards to resonance modes and directional beam emission by means of photonic nanojets [2]. The unique feature of nanojets is a directional beam with a beam waist smaller than the diffraction limit. In fact, a transverse beamwidth as small as 0.3 X has been reported [3]. In contrast to diffraction-limited microlensing, the nano-jet phenomenon is a near-field effect due to the proximity of the focus position and the microsphere surface. Also because of the nano-scale beam waist, the photonic nano-jets can reach a very high intensity. This offers new opportunities for a broad range of applications in biophotonics, plasmonics, optical data storage and ultramicroscopy. One of the motivations for our research is to examine the feasibility of subdiffractional resolution of imaging and sub-wavelength optical signal waveguiding.

© 2009 IEEE